I. Field
This disclosure relates to geopolymer or other concrete-like materials using algae-produced materials for plasticizers and/or accelerants.
II. Background
The term “geopolymer” refers to a class of synthetic aluminosilicate materials with potential use in a number of areas, but predominantly as a replacement for Portland cement. Compared to Portland cement, geopolymers have lower carbon dioxide production emissions, greater chemical and thermal resistance and better mechanical properties at both atmospheric and extreme conditions.
Geopolymers are generally formed by reaction of an aluminosilicate powder with an alkaline silicate solution at roughly ambient conditions. Conventional geopolymers can be made from natural sources of pozzolanic materials, such as lava or fly ash from coal. Most studies have been carried out using natural or industrial waste sources of metakaolin and other aluminosilicates.
A particular ingredient used in the production of concrete and geopolymers is known as a “plasticizer.” Plasticizers are water reducers or dispersants that can be added to concrete/geopolymer mixtures to improve workability. Generally, the strength of a concrete is inversely proportional to the amount of water added or water-cement (w/c) ratio. In order to produce a stronger concrete/geopolymer, less water is added. Too little water, however, “starves” the mix, which makes the concrete/geopolymer mixture very unworkable and difficult to mix, necessitating the use of plasticizers.
In ancient times, the Romans used animal fat, milk and animal blood as a plasticizer for their concrete mixes. More modern plasticizers are commonly manufactured from lignosulfonates and sulfonated napthalene, better known as sulfonated melamine or formaldehyde. These chemicals are by-products from the paper manufacturing.
Unfortunately, such chemicals can be toxic and environmentally unfriendly, and use of such plasticizers requires dependency of the formidable infrastructure needed to produce such chemicals. Accordingly, new and more environmentally friendly approaches to the production of plasticizers are desirable.